The field of art to which this invention pertains is derivatives of carbohydrate gums and particularly, organic gels of such carbohydrate gum derivatives.
Natural and synthetic gums have been used as thickeners for foods, coatings, paints, explosive slurriers, oil well fluids and many other applications. One such natural gum which has found many applications as a thickener is locust bean gum, or carob bean gum as it is also known. One limitation in the use of locust bean gum is its limited solubility and viscosity increase in cold water, i.e., water at 25.degree. C. or below. Although the solubility and viscosity increase with increasing temperature, a minimum temperature of about 86.degree. C. is required to obtain maximum solubility and viscosity. Upon cooling, the solubility and viscosity of the locust bean gum solutions are retained.
As described in U.S. Pat. No. 3,557,016, heat reversible gels are obtained from a blend of locust bean gum and xanthan gum. These gels are made by adding a mixture of the locust bean gum and xanthan gum to hot water and, thereafter, cooling, or by adding the mixture of gums to cold water and mixing under high speed agitation. Generally such gels are obtained by adding the mixture of gums to hot water in the temperature range of about 66.degree. C. to about 82.degree. C. and holding the components in this temperature range for about 15 minutes. The crosslinking reaction between locust bean gum and xanthan gum which results in the highly viscous gels is unique for these materials. In fact, this reaction and gel formation is used as a test for the determination and identification of locust bean gum as described in U.S. Food Chemical Codex II, page 856.